Kate Upton: Price I Paid to Be on SI Cover

Two-time Sports Illustrated Swimsuit cover model Kate Upton has yet to reach her 21st birthday and may already be a household name.

Upton, who turns 21 in June, has now graced the cover in back-to-back years: in 2012 as Sport Illustrated Swimsuit's Rookie of the Year and again in 2013 with a photo from the first ever fashion shoot in Antarctica.

"It was an adventure for sure," Upton told CNBC in-studio Tuesday. "It's freezing there, obviously. No one knew what to expect. You had to go the land in these zodiac boats, kicking ice just to get the rafts through."

Upton, who hails from Florida, said she experienced hearing and eyesight loss after returning from the Earth's southernmost continent. "If I didn't get sick standing in Antarctica in a bikini, something would be wrong with me. I'd probably be Wonder Woman or something."

Managing the Kate Upton Brand

CNBC's Brian Shactman speaks with Kate Upton, Sports Illustrated Swimsuit Edition cover model of 2012 and 2013, and Mark Ford, Time INC. Sports Group president about shooting in Antarctica.

The model has Sports Illustrated to thank for propelling her into superhero status in 2012.

"Everything's changed," she said, reflecting back a year. "I have so many opportunities now with different clients and I think for me what's really exciting is now I get to choose which clients I work with, so I can do products or shoots that I really love and I really believe in."

Upton, with more than 1.1 million combined followers on Twitter and Facebook, is undoubtedly loved by fans across the world. "We can finally talk about Antarctica!!!!!" Upton tweeted when Sports Illustrated officially revealed the news. "Took us 2 months to thaw out."